The two key Characters featured in the deck, Jack-Jack Parr, Incredible Potential and Mrs
First of all, mana abilities do not use the stack, so as soon as you use the ability (like tapping a land), you get the mana
Spiteful Repossession: Land ramp is quite commonplace in Commander, but there arent always many ways to fight back against it outside of blowing up lands
Turn three cast Kodamas Reach: Turn four we cast Heartbeat of Spring and use the extra mana it generates to active Krosan Verge: On Turn Five we cast Turnabout floating **WWUURRBBGG and cast Tiamat searching for Morophon, Miirym, Terror of the Peaks, Niv-Mizzet Reborn, and Scion of the Ur-Dragon and cast them in that order
This is pretty similar to the first argument, that youll draw your best cards less often, but it highlights that its even more likely that you have some cards that are wildly better than your other cards in post-sideboard games
Cards like The One Ring and Orcish Bowmasters dominated the Constructed scene until the digital nerf took place